The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was syn...The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.展开更多
An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electroly...An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electrolyte(DLi)is proposed with specific sheath structure to build stable interface on the LiNi_(0.8)Co_(0.1)Mn_(0.1O2)(NCM811)cathode at wide operating temperature between−60 and 55℃.Lithium perchlorate(LiClO_(4))in combination with high concentration lithium bis-(trifluoromethanesulfonyl)imide(LiTFSI)strengthens the internal interaction between anion and cation in the solvation structure,increasing Li+transference number of the electrolyte to 0.61.Moreover,the structure and component characteristics of the passive interface layer on NCM811 are modulated,decreasing desolvation energy of Li+ions,benefiting Li+transport dynamics especially at low temperature,and also ensuring the interfacial stability at a wide operating temperature range.As a result,the cathode with DLi exhibits excellent high-temperature storage performance and high capacity retention of 80.5%in 100 cycles at 55℃.Meanwhile,the Li||NCM811 cells can deliver high discharge capacity of 160.1,136.1,and 110.3 mAh·g^(−1)under current density of 0.1 C at−20,−40,and−60℃,maintaining 84.5%,71.8%,and 58.2%of the discharge capacity at 30℃,respectively.Moreover,it enables NCM811 cathode to achieve a reversible capacity of 142.8 mAh·g^(−1)in 200 cycles at−20℃and 0.2 C.Our studies shed light on the molecular strategy of wide operational temperature electrolyte for high nickel ternary cathode.展开更多
超高镍层状材料LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)(简称NCM92)因其具有较高的能量密度和价格优势,已成为锂离子电池重要的正极材料来源之一。然而,由于该材料的界面不稳定和不可逆相变,商业应用面临特别是在高截止电压下快速的容量衰...超高镍层状材料LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)(简称NCM92)因其具有较高的能量密度和价格优势,已成为锂离子电池重要的正极材料来源之一。然而,由于该材料的界面不稳定和不可逆相变,商业应用面临特别是在高截止电压下快速的容量衰落和严重的结构退化的问题。本研究设计了一种ZrO_(2)/Li_(2)ZrO_(3)双包覆层改性超高镍单晶正极材料,同时材料表面均匀掺杂有Zr元素,通过双包覆层协同策略显著增强了正极的高压性能和结构稳定性。研究结果表明,ZrO_(2)/Li_(2)ZrO_(3)双包覆层可以有效缓解超高镍正极材料H2-H3相变的不可逆性,提高力学稳定性和界面稳定性,同时表面Zr掺杂进入晶体结构中的TM层与Li位抑制Li/Ni混排并扩宽了晶格间距,ZrO_(2)/Li_(2)ZrO_(3)双包覆层与Zr掺杂改性的材料(NCM92-Zr)展现出优异的电化学性能,在0.5 C(200 mA·g^(-1))电流密度下,2.75~4.4 V电压范围内循环150圈后仍有155.2 mA h g^(-1)的放电比容量,容量保持率高达75.5%。此研究为在高截止电压下超高镍正极的复杂机制和改进的结构稳定性提供了新的思路。展开更多
文摘The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.
基金supported by the National Natural Science Foundation of China(Nos.52172180 and 51872026)the National Key R&D Program of China(No.2018YFB0104300).
文摘An adequate wide temperature electrolyte for high nickel ternary cathode is urgent to further develop high energy density batteries.Herein,a comprehensive double-salt local high-concentration sulfolane-based electrolyte(DLi)is proposed with specific sheath structure to build stable interface on the LiNi_(0.8)Co_(0.1)Mn_(0.1O2)(NCM811)cathode at wide operating temperature between−60 and 55℃.Lithium perchlorate(LiClO_(4))in combination with high concentration lithium bis-(trifluoromethanesulfonyl)imide(LiTFSI)strengthens the internal interaction between anion and cation in the solvation structure,increasing Li+transference number of the electrolyte to 0.61.Moreover,the structure and component characteristics of the passive interface layer on NCM811 are modulated,decreasing desolvation energy of Li+ions,benefiting Li+transport dynamics especially at low temperature,and also ensuring the interfacial stability at a wide operating temperature range.As a result,the cathode with DLi exhibits excellent high-temperature storage performance and high capacity retention of 80.5%in 100 cycles at 55℃.Meanwhile,the Li||NCM811 cells can deliver high discharge capacity of 160.1,136.1,and 110.3 mAh·g^(−1)under current density of 0.1 C at−20,−40,and−60℃,maintaining 84.5%,71.8%,and 58.2%of the discharge capacity at 30℃,respectively.Moreover,it enables NCM811 cathode to achieve a reversible capacity of 142.8 mAh·g^(−1)in 200 cycles at−20℃and 0.2 C.Our studies shed light on the molecular strategy of wide operational temperature electrolyte for high nickel ternary cathode.
文摘超高镍层状材料LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)(简称NCM92)因其具有较高的能量密度和价格优势,已成为锂离子电池重要的正极材料来源之一。然而,由于该材料的界面不稳定和不可逆相变,商业应用面临特别是在高截止电压下快速的容量衰落和严重的结构退化的问题。本研究设计了一种ZrO_(2)/Li_(2)ZrO_(3)双包覆层改性超高镍单晶正极材料,同时材料表面均匀掺杂有Zr元素,通过双包覆层协同策略显著增强了正极的高压性能和结构稳定性。研究结果表明,ZrO_(2)/Li_(2)ZrO_(3)双包覆层可以有效缓解超高镍正极材料H2-H3相变的不可逆性,提高力学稳定性和界面稳定性,同时表面Zr掺杂进入晶体结构中的TM层与Li位抑制Li/Ni混排并扩宽了晶格间距,ZrO_(2)/Li_(2)ZrO_(3)双包覆层与Zr掺杂改性的材料(NCM92-Zr)展现出优异的电化学性能,在0.5 C(200 mA·g^(-1))电流密度下,2.75~4.4 V电压范围内循环150圈后仍有155.2 mA h g^(-1)的放电比容量,容量保持率高达75.5%。此研究为在高截止电压下超高镍正极的复杂机制和改进的结构稳定性提供了新的思路。
